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The use of health-related quality of life (HRQOL) in children and adolescents as an outcome criterion to evaluate family oriented support for young carers in Germany: an integrative review of the literature

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Abstract

Background

Young people below the age of 18, whose lives are affected by looking after a relative
with a disability or long-term illness, are called young carers. Evidence based family
oriented support for young carers and their families in Germany is currently being
developed. To allow for scientific evaluation, an outcome criterion needs to be chosen.
Until today, there are no assessment instruments available, which focus on young carer's
specific demands and needs. As HRQOL seems to be an adequate alternative outcome criterion,
an integrative review of the literature was carried out to verify this assumption.

Methods

The aim of the integrative review was to get information about a) the concept and
the common definition of HRQOL in children, b) preferable HRQOL assessment techniques
in children, and c) the relevance of HRQOL measures for the population of young carers.
An additional aim of the review was to give advice on which instrument fits best to
assess young carer's HRQOL in Germany. Searches were conducted in PubMed in order
to obtain papers reporting about a) the development or psychometric assessment of
instruments measuring HRQOL in children and adolescents up to the age of 18, and b)
on the conceptual framework of HRQOL in children.

Results

HRQOL is a multidimensional construct covering physical, emotional, mental, social,
and behavioural components of well-being and functioning as subjective perceived by
a person depending on the cultural context and value system one is living in. Young
carer's problems and needs are well covered by these common domains of HRQOL. Since
no specific HRQOL-measures are available to address young carers, a generic one has
to be chosen which a) has been created for use in children, b) allows self- and proxy-report,
and c) has good psychometric testing results. Comparing four generic measures with
currently best published psychometric testing results, items of the KIDSCREEN cover
young carer's specific problems most accurate.

Conclusion

The KIDSCREEN questionnaires seems adequate to evaluate the intervention as their
items cover young carer's needs and problems most accurate.

Background

It is well described that chronic illness not only affects the person concerned, but
also the entire familial system [1-6]. Psychological distress and physical demands of caregiving can seriously compromise
the quality of life (QOL) of a family caregiver [7-9]. As children might be involved in caring for their relatives -or even become the
primary care giver – their burden has to be taken into account as well. These young
people below the age of 18, whose lives are affected by looking after a relative with
a disability or long-term illness, are called young carers [10,11]. A UK census [12] identified the prevalence of young carers as 1.5 percent of all children below the
age of 18, which means that approximately 175,000 children in the UK are affected
[13]. There is no current evidence about the prevalence in other countries. Results of
national surveys in the UK state that children are in average between 8 and 10 years
old when they get involved in caring for a relative, while the avarage age of young
carers is 12 years [14,15]. While 84% of the young carers spend less than 20 hours a week with caring tasks,
9% are looking after a relative up to 50 hours a week [12]. The kind of help comprises all areas of caring and housekeeping [11,15-20], and the amount of help ranges from assistance to sole responsibility [16,18,21,22]. According to Dearden and Becker [15], "housekeeping" and "general care" are the main activities of young carers to help
their family members (table 1). Researchers from the UK refer to the vulnerability of families concerned and they
predict that children will be affected in their whole development if the families
stay without support [18,23]. Currently, there are more than 300 young carers projects available in the UK, where
these children are supported and counseled [24].

Young Carers in Germany

In Germany, hardly anything is known about the situation of children, who are involved
in caring for their relatives, and, as a consequence, there are no specific support
services available. There is no current evidence about the prevalence in Germany,
but if the British prevalence data [12] was adopted then there would be approximately 225,000 young carers in Germany. Young
carer's personal and familial situation in Germany, their family's needs and expectations
have recently been explored in a Grounded Theory study [25,26]. The aim of the study was to gain insight into experience and construction of familial
care, in which children take over an active role, in order to work out a basis for
the conception of specific family oriented support. One main focus of the study lies
on effects on the children and their expectations in outside support. The study's
results confirm that young carers might suffer from their situation in several ways
[25,26]:

• having no one to talk to

• living in secrecy

• lack of freetime

• social isolation and loss of childhood

• problems in school and missing time in school

• strong parental attachment

• feelings of loneliness, sadness, fear and shame

• physical and mental exhaustion

These findings point out the need for support for families concerned. Therefore, the
aim of a current study is to develop, implement and evaluate evidence based family
oriented support for young carers and their families in Germany. The intervention's
concept a) is based on Metzing's [25,26] results, b) is based on expert interviews with project leaders and young carers themselves,
c) focuses on the individual needs of families and d) has to allow for scientific
evaluation. The aim of family-oriented support for young carers and their families
is to disburden their situation and reduce the risk of negative impact. This study
is a project of the Nursing Research Network North-Rhine-Westphalia [27], and it is funded by the German Federal Ministry of Education and Research (BMBF,
project funding reference number 01GT0619).

Although young carers projects are well established in the UK, hardly any project
has been evaluated with a standardized assessment instrument.

Aim

At present, there are no specific assessment instruments available, which focus on
young carer's situation, demands and needs. In order to allow scientific evaluation,
an outcome criterion measuring the effectiveness of specific support has to be chosen.
As health-related quality of life (HRQOL) in children has become an important outcome
indicator in evaluating health-care interventions, it may be well used for the evaluation
of young carers support. To verify the assumption, an integrative review of the literature
has been carried out. If the review confirms HRQOL to be suitable, an additional aim
of the review is to give advice on which instrument fits best to assess young carer's
HRQOL in Germany. In what follows, results of this review will be presented.

Methods

The review follows the method described by Polit and Hungler [28]. The following questions were addressed to the literature:

• What is the concept and the common definition of HRQOL in children?

• How can HRQOL be assessed in children and which assessment-technique is preferable?

• Are the dimensions and items of existing HRQOL measures of relevance for young carers?

A PubMed database search was carried out using keywords such as "children", "adolescent",
in combination with "health-related quality of life", "quality of life", "HRQOL" and
"QOL" (figure 1). In addition, references from eligible articles were hand-searched.

Inclusion and Exclusion criteria

The search was restricted to documents written in English or German.

Articles published between 1998 and 2008 were included, if they reported about the
development or psychometric assessment of instruments measuring HRQOL in children
and adolescents up to the age of 18. Papers, reporting on the conceptual framework
of HRQOL in children were also included. Documents were excluded if the measures used
were not originally designed for use in children or adolescents.

Procedure

Documents identified by the search were checked for relevance by one reviewer (JgS).
Data from documents considered eligible for inclusion was extracted using the software
MAXqda. Content of documents was structured using the following categories: a) definition
and concept of HRQOL, dimensions and factors of HRQOL, b) measurement instruments,
development, country of origin, population, type of respondent, age group.

Results

In sum, 317 papers were found, of which 64 fit the inclusion criteria. Of these, 36
were regarded as being relevant for this review. Five systematic reviews were found.
Three focused on identification and evaluation of all available measures of HRQOL
in children [29-31], two on conceptual framework of HRQOL in children [32,33]. These reviews gave valuable information about children's HRQOL in general, and were
helpful for finding further important literature. In total, 43 documents were included
in this review.

Health-related quality of life in children and adolescents

Quality of Life (QOL) is a complex, abstract, and multidimensional concept which is
difficult to define and has relevance to virtually all areas of human function [34]. HRQOL is a main part of QOL and is considered to be an important construct in describing
one's overall condition within the health context [35-38]. Generally it is conceptualized as a multidimensional construct built up by several
domains [39-42]. There is some consensus considering physical, emotional and social aspects of health
to be core domains of HRQOL [43-45], which follows the WHO definition of health as a state of complete physical, mental,
and social well-being, and not merely the absence of disease or infirmity [46].

Nevertheless, the overall quantity of domains differs in the literature. For example,
"behavioural, cultural, and psychological dimensions" as well as "a global perception
of health and well-being" are regarded as important domains of HRQOL [30,36]. Depending on the population under study, HRQOL domains consist of several various
specific dimensions or factors [47]. For example, physical factors might include aspects such as selfcare, pain, or mobility,
while social factors might include aspects such as friends, work, or family. These
differences in quantity of domains and dimensions lead to widely varying definitions
of HRQOL. Based on a commonly accepted definition by the WHO Quality of Life group
[48], the following operational definition as stated by von Rüden [35] is used in this paper:

HRQOL is a multidimensional construct covering physical, emotional, mental, social,
and behavioural components of well-being and functioning as subjective perceived by
a person depending on the cultural context and value system one is living in.

Since this definition applies to HRQOL of any person, the specific aspects of a child's
life lead to different extracts and weightening of domains and factors compared to
adolescents or adults [41]. Regarding "social components" for example, children state "family", "peer group"
and "school" to be important factors [41,49,50]. While younger children consider "family" as the most important, adolescents highlight
"peers" [49,50]. Furthermore, in comparison with adults, children have only limited capabilities
to move from disadvantageous environments [36]. Thus, social context might have more influence on children's HRQOL than on adult's.

HRQOL research in children

According to Ravens-Sieberer et al. [40,51] the development of HRQOL research in children occurred in three phases. The first
phase in the late 1980s was concerned with the theoretical concept of HRQOL in children,
especially in contrast to adults. During the second (still ongoing) phase, which started
in the early 90s, several HRQOL measures for children have been developed. The third
phase, from 1995 onwards, emphasizes the application of these measures in clinical
and epidemiological studies (ibid.). In the meantime, HRQOL in children has become
an important outcome indicator a) in evaluating health-care interventions, b) in identifying
health inequalities, c) in detecting subgroups at risk within the general population,
and is d) used in epidemiological studies and health surveys [30,51]. Knowledge about children's HRQOL is of specific interest in public health research
as it is the basis for HRQOL in adulthood [43]. Therefore, research assessing the HRQOL status of children has been carried out
in many countries. Findings show that there are age-, gender- and socioeconomic-related
differences in children's HRQOL. Children up to the age of 12 report higher HRQOL
than adolescents [40,43,52]. As they get older, adolescent girls show lower HRQOL than boys, especially in the
domains of emotional and physical well-being (ibid.). In general, children and adolescents
with a high familial socioeconomic status report higher HRQOL than those less affluent
[40,53].

Measuring HRQOL in children and adolescents

At the beginning of HRQOL research in children, measures for adults had been modified
to fit for children [51,54]. Today, there is a clear agreement that instruments originally developed for adults
are not applicable to assess children's HRQOL [55]. Besides a different understanding of health and health-related domains and dimensions,
children's emotional and cognitive development have to be taken into account [40,56]. Therefore, measures especially for the use with children have been created.

Development of measures

HRQOL can be considered as a latent theoretical construct which cannot be measured
directly but only indirectly using indicators [35,57]. While most of the early instruments were based on expert opinions about important
HRQOL domains [50], several new questionnaires preferred the use of focus groups with children to reflect
their opinions and ideals of HRQOL in order to identify relevant domains and dimensions
[29,36,50,58]. However, due to children's cognitive development and rising awareness, it has to
be taken into account that their concept of health changes as they mature [59]. Addressing these developmental differences, measures are created in multiple forms,
each designed for a different age group [41], since item statements have to consider the cognitive developmental level of the
children at different ages [41,42,51]. This means that tools such as likert scales need to be considered from the perspective
of the child's ability to understand and may require adaption using pictograms or
smileys [51]. In addition the number of questions should also be limited as younger children can
process up to less items than older [41,42]. Another possible approach is to identify relevant items which are understood by
and function in comparable ways across different age groups [36].

As the process of HRQOLresearch in children went on, it has been regarded as a limitiation
that measures were developed in only one country and then were translated for use
in other countries without regard to cultural differences [60,61]. As the connotation of HRQOL shows cultural differences (ibid.), these instruments
cannot be used offhand for comparing populations across different countries without
difficulties. A translated version must therefore undergo new tests for validity and
reliability before it can be relied upon for usage in that country or culture. To
avoid this problem, it has been recommended to simultaneously develop a measure across
different countries using focus groups [40,50,62].

Generic and specific approach

There are two general types of HRQOL instruments: generic and specific ones. Generic
measures are used to get information about HRQOL on healthy as well as on ill children
in different populations, conditions, and settings. Thus, these results can be compared
across groups [29,30]. Specific measures are designed to be valid for a specific disease or population
and aim to gather information on specific disease-symptoms or health-problems [63]. Compared to generic, specific measures tend to be more sensitive to changes arising
from changes in conditions and may, therefore, be more effective in identifying intervention
effects [41,63]. On the other hand they cannot be used to compare HRQOL across conditions and settings.
Some measures are now being developed incorporating both a generic core and disease-specific
modules [29]. A recent review [30] identified a total of 94 instruments that focus on children. Of these, 30 are generic
and 64 are disease-specific (ibid.). Nevertheless, authors still complain about the
limited availability of specific instruments for certain diseases [29,31]. At this time, there are no specific instruments available for measuring HRQOL of
young carers. Thus, generic instruments are warranted for the use in this population.

The proxy-problem

There are two main approaches to assess HRQOL in children: self- and proxy-report.
By using self-report, the child's self-perception of HRQOL is measured. While in the
past, children often were regarded as unreliable respondents due to their cognitive
immaturity, limited social experience, and continued dependency [64], early measures were based on data provided by parents or other proxies (e.g. medical
staff) [44,55,65,66]. Thus, the proxy's perception of a child's HRQOL is assessed. These two approaches cannot be considered to measure
identical constructs and research findings confirm a moderate correlation only [42,66-69]. The level of agreement between parents and children appears to depend on the observability
of a certain dimension, with generally good agreement reflecting physical dimensions
and poor agreement reflecting social and emotional dimensions [65,66,68]. Davis [42] states that proxy-discordance is due to differences in parent's and children's response
styles, interpretation of items, and reasons for answering. Besides this, Cremeens
et al. [68] concern that artefact of statistical methods may have also caused proxy-disagreement
in former research.

Nevertheless, according to the concept of HRQOL, the individual's own subjective perception
should be measured to get valid data. This is true for children as well as for adults.
Recent research shows, that children as young as eight [50,70] and even at the age of six years [44,70,71] can reliably and validly self-report their HRQOL status if the questionnaire is age- and cognitive-appropriate. In detail, measures for young
children should a) address their writing and reading skills [51], b) consider alternative assessment methods as pictograms or smileys [51], and c) avoid Likert-Scales in order to prevent extreme answers [41,42].

Because neither the child's self report nor the parent's proxy report is without bias,
Eiser [66] suggests that obtaining information from both may provide the most complete picture
of HRQOL.

Selecting an HRQOL instrument

When selecting a HRQOL instrument, it is important to consider whether the questionnaire
suits the purpose of the intervention, whether it covers important domains and dimensions
relevant to the context and whether it fits the age group under study [30,72]. In addition, there should be sufficient psychometric testing of the instrument.

Relevance of HRQOL dimensions and measurement items for use in young carers

According to the definition as stated by von Rüden [35], young carer's problems and needs (as worked out by Metzing [25,26]) are well covered by the core domains of HRQOL (table 2). Their problems are mainly related to the social domain and its factors, followed
by the emotional and mental domain. One problem is covered by the physical domain.

Solans et al. [30] present a detailed overview of available generic and specific measurements including
information about covered HRQOL domains and psychometric testing. The PubMed search
added no additional instrument to this list. According to Solans et al. [30], there are four generic measures with the best published psychometric testing results:
CHQ [73], KINDLR[58], KIDSCREEN [36], and PedsQL 4.0 [74]. Each of these instruments covers nearly all domains and factors, which are relevant
for young carers (table 3), and they also have a German version (the KINDLR is an original German measure). The CHQ only omits the factor "leisure", both KINDLR and KIDSCREEN omit the mental dimension, and PedsQL omits the mental dimension and
the factor "family".

Comparing the instruments' items in detail, as shown in additional file 1, there are differences in how accurate the specific problems of young carers are
addressed. Items of the CHQ don't address the problems "lack of freetime" and "physical and mental exhaustion".
The item "I feel lonely" allows to refer to the problems "having no one to talk to",
"living in secrecy", "social isolation" and "loneliness, sadness, fear". The problem
"living in secrecy" is only addressed indirectly by the items "I lied/cheated" and
"I feel lonely".

The KIDSCREEN allows to link its items to all problems of young carers. Four items are related to
more than one problem: The item "have you had enough time for yourself" may be an
indicator for the problems "lack of freetime" and "parental attachment", while "have
you spent time with your friends" points to "lack of freetime" and "social isolation".
The item "have you felt so bad that you didn't want to do anything" refers to "loneliness,
sadness, fear" and "physical and mental exhaustion", while the item "have you felt
lonely" allows for the same multiple link as CHQ's "I feel lonely". The problem "living
in secrecy" is only allusively addressed by the items "have you felt lonely" and "have
you been able to rely on your friends".

Items of the KINDLR allow for covering all problems of young carers. Comparable to KIDSCREEN, two of KINDLR's items refer to several problems. The item "I played with my friends" points to
the problems "lack of freetime" and "social isolation", while the item "I felt alone"
allows for the same multiple link as KIDSCREEN's "have you felt lonely" and CHQ's
"I feel lonely". Comparable to CHQ and KIDSCREEN, the problem "living in secrecy"
is only allusively covered by the single item "I felt alone".

The PedsQL does not represent the problems "having no one to talk to", "living in secrecy" and
"parental attachment". Two of its items point to multiple problems. While the item
"I cannot do things that other kids my age can do" refers to the problems "lack of
freetime" and "social isolation", the item "I forget things" indicates decreased ability
to perform at school and is an indirect measure of the effect of "physical and mental
exhaustion".

To summarise, both CHQ and PedsQL don't match two problems of young carers, whereas
items of KIDSCREEN and KINDLR allow for addressing all of them (additional file 1). Furthermore, KIDSCREEN seems to be more accurate to address young carer's problems
than the other instruments. The problem "having no one to talk to" is indirectly covered
by CHQ's item "I feel lonely" and KINDLR's "I felt alone" while KIDSCREEN additionally asks "have you been able to talk to
your parents when you wanted to" and "have you and your friends helped each other".

The problem "lack of freetime" is covered allusively by KINDLR's questions "I was bored" and "I played with friends", while PedsQL's item "I cannot
do things that other kids my age can do" allows for an indirect link. In contrast,
KIDSCREEN directly asks "have you had enough time for yourself" (additional file 1).

Regarding the problem of strong "parental attachment", the CHQ only assess the family's
general "ability to get along with one another". The KINDLRasks whether "my parents stopped me from doing certain things", which can be understood
as active parental interdictions. KIDSCREEN's item "have you been able to do the things
you want to do in your free time" however allows to cover leisure activities which
are unfeasible due to parental impairment.

Discussion

testing results. The literature supports the use of HRQOL with young carers as its
domains cover the problems they experience. Thus, HRQOL seems to be a suitable outcome
criterion measuring the effectiveness of special young carers support. As HRQOL in
children has become an important outcome indicator in evaluating health-care interventions,
there are several measurements available. Since no specific HRQOL-measures are available
to address the specific situation of young carers, a generic one has to be chosen
for use in this population. The literature advises to select a measure, which a) has
adequate psychometric testing results, b) allows for self and proxy assessment, c)
has been devloped in the country of origin or crosscultural, and d) which items cover
important domnains relevant to the context.

According to Solans et al. [30], the CHQ [73], KIDSCREEN [36], KINDLR[58], and PedsQL 4.0 [74] are generic measures with the best published psychometric testing results. In addition,
all of these fulfill the request of self and proxy assessment. Concerning their developmental
process, there is a difference between the four. While CHQ, KINDLR and PedsQL were designed within a single country and have been translated into several
languages afterwards, only KIDSCREEN was developed simultaneously across 13 European
countries (Germany included). The most important difference between the four instruments
was found while comparing how sensitive the instruments' items cover the context under
study. As described before, KIDSCREEN turns out to be the most accurate instrument,
and thus will be used for evaluating young carers support service. Nevertheless, some
of young carer's problems are not directly matched by the instruments. For example,
regarding the problem "having no one to talk to" it would be helpful to ask "do you
have the feeling, that there is no one you can talk to". Concerning "living in secrecy",
a question like "do you have to conceal something" would be adjuvant. This shows that
although HRQOL measures allow for addressing young carer's problems, there is still
a need to develop instruments which are desinged for use in this specific population.

This even rises the question, whether we need to broaden our understanding of outcome
measures. In order to find an appropriate outcome criterion for family oriented support
of young carers, we focused on individual HRQOL instruments. But if we adopt a family
oriented perspective, an outcome criterion might need to address the family system
as a whole. For example, for adult care givers, there are measures available which
assess the impact and burden a chronically ill child has on the family (e.g. the "Impact
on Family Scale" [75], which has a German version [76]). However, these measures are related to specific topics, and until today none of
them focuses on the situation of young carers and their families. In addition, they
are designed for the use in adults only. On the other hand, although young carers
support needs to be family oriented, the focus of our current study still lies on
the children, their experiences and well-being. Nevertheless, future research on instrument
development for use in the population of young carers and their familie should consider
a systematic approach.

Conclusion

The literature approves HRQOL to be an adequate alternative criterion to evaluate
the effectiveness of a support service for young carers. Comparing available HRQOL
measures, the KIDSCREEN questionnaires fit best to assess young carer's HRQOL in Germany,
as

• young carer's specific problems are well-covered by KIDSCREEN's items,

• it allows for both self- and proxy assessment,

• it shows good psychometric testing results,

• it was developed cross-culturally, including Germany.

Nevertheless, as some of young carer's specific problems are not directly addressed
by current HRQOL measures, there is a need to develop instruments focusing on this
specific population.

Limitation

The manuscript is not a systematic but an integrative review. This is due to the reason
that there are currently neither RCTs evaluating young carers support services nor
assessment instruments focusing on young carers' specific situation available.

The literature search was carried out in PubMed only.

Only items of the four instruments with the best published psychometric testing results
where analysed.

Recommendation for future research

The results of the literature search show a lack of standardised measures designed
for the use in young carers, and thus implicates three possible approaches: a) to
develop independent instruments focusing on the specific problems of young carers,
b) to develop specific young carers modules which can be connected to the generic
core of available HRQOL-measures (e.g. the KINDLR), and c) to develop instruments for the use in children, which have a systematic
view on the impact that chronic illness has on the entire family.

Competing interests

The authors declare that they have no competing interests.

Authors' contributions

JgS carried out the literature search, included and excluded documents, and wrote
the manuscript. SMB and WS revised it critically for important intellectual content.
All authors read and approved the final manuscript.

Acknowledgements

We would like to thank the three native speakers Angelique Duquesne and Alexa Cintron,
Florida International University, and Gareth Parson, University of Glamorgan, for
revision of this manuscript.

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